Abstract

Background To test for cross-sectional (at age 11) and longitudinal associations between objectively measured free-living physical activity
(PA) and academic attainment in adolescents.Method Data from 4755 participants (45% male) with valid measurement of PA (total
volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (ALSPAC) was examined.
Data linkage was performed with nationally administered school assessments in English, Maths and Science at ages 11, 13 and
16.

Results In unadjusted models, total volume of PA predicted decreased academic attainment. After controlling for total volume of PA,
percentage of time spent in moderate-vigorous intensity PA (MVPA) predicted increased performance in English assessments in
both sexes, taking into account confounding variables. In Maths at 16 years, percentage of time in MVPA predicted increased
performance for males (standardised β=0.11, 95% CI 0.00 to 0.22) and females (β=0.08, 95% CI 0.00 to 0.16). For females the
percentage of time spent in MVPA at 11 years predicted increased Science scores at 11 and 16 years (β=0.14 (95% CI 0.03 to
0.25) and 0.14 (0.07 to 0.21), respectively). The correction for regression dilution approximately doubled the standardised
β coefficients.

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